An enigmatic beast mentioned in the Welsh poem The Spoils of Annwn.
It is unclear if the ox had any connection with Arthur. A Triad names the Speckled Ox as one of the “three prominent oxen” of Britain. It may be related to the Spotted Ox from Culhwch and Olwen.
Source
Preiddeu Annwfn | Attributed to Taliesin, c. 900